Let $f$ be defined by $$f(x) = \begin{cases} 3 x+ m, & x < 2 \\ -6 x^2 + 2m, & x \geq 2 \end{cases}$$ (a) Find (in terms of $m$)

$\displaystyle{\lim_{x\rightarrow 2^{+}} f(x)}$ =

(b) Find (in terms of $m$)

$\displaystyle{\lim_{x\rightarrow 2^{-}} f(x)}$ =

(c) Find the sum of all values of $m$ such that $$\lim_{x\rightarrow 2^{-}} f(x) = \lim_{x\rightarrow 2^{+}} f(x)$$ Sum of values of $m$ =